Mangroves are uniquely important ecosystems, for preserving biodiversity, sustaining livelihoods, and mitigating against climate change. However, they are degraded globally and are therefore a priority for ecosystem restoration. To date, the assessment of mangrove restoration outcomes is generally poor, and the limited studies that do exist are focused largely on forest area. Thus, more holistic ways of assessing the outcomes of mangrove restoration projects on biodiversity and associated ecological processes are urgently needed. Ecological networks are a useful tool for simultaneously examining both. Here, we assessed the utility of using species‐interaction networks for evaluating mangrove restoration outcomes for the first time. We compared the structure and complexity of mangrove ecological networks in replicated “monoculture reforestation,” “mixed species regeneration” and “reference forest” plots in two study areas in Sulawesi, Indonesia, an estuarine, and a coastal fringe mangrove system. We also combined and evaluated sampling methods, utilizing traditional plant–animal sampling while also integrating video recording data in a novel way. We found significant differences in the structure and complexity of mangrove networks between restored and natural plots, with contrasting effects between the two sites. Our results show differences in the complex ways in which taxa interact in mangrove restoration projects, which would be overlooked if common biodiversity metrics, such as species richness, were used alone, with consequences for the restoration of ecosystem functioning. We also highlight the utility of video recording data collection for constructing species‐interaction networks, overcoming the detrimental impacts of observer presence for some key species.

Djamaluddin R, Brown B, Lewis III RR. 2019. The practice of hydrological restoration to rehabilitate abandoned shrimp ponds in Bunaken National Park, North Sulawesi, Indonesia. Biodiversitas 20: 160-170. The world has lost a large extent of mangroves, while rates of recovery of these ecosystems from natural re-growth and restoration are slow. We developed a hydrological restoration technique to investigate the importance of hydrological modification in mangrove restoration success. Ecological Mangrove Restoration was adopted to restore abandoned shrimp ponds at Tiwoho, Bunaken National Park, North Sulawesi. Hydrological modification resulted in the creation of various mangrove sub-habitat conditions. These conditions remained unstable within the first three years and became relatively stable after seven years. Tidal inundation and soil surface salinity appeared to be the major factors controlling mangrove establishment and growth. All natural recruits and planted trees grew faster and produced more propagules/fruits within a short period of time after the normal physical conditions achieved. The restored site was covered by approximately 91.3 % of vegetation with the same canopy species composition as the natural stands. The practiced hydrological restoration method was simple, cost-effective and can help other practitioners in improving their mangrove restoration techniques.

Abstract. Djamaluddin R. 2019. Growth pattern in tropical mangrove trees of Bunaken National Park, North Sulawesi, Indonesia. Biodiversitas 20: 1713-1720. Seasonal diameter growth patterns in mangrove are often related to rainfall, temperature and moisture regime. At any localities, specific environmental factors may influence growth rate of individual trees. I asked whether stem growth of tropical mangrove in BNP is constant over a year, and whether stem growth rates are different by sites, species, and trees of the same species. Dendrometer bands were installed on trees from twelve different sites in BNP to measure stem growth rates. Measurements were made at two months intervals from July 1999 to June 2001 and March 2014 to December 2016. Growth rates measured in trees at the twelve sites varied significantly from 0.83 ± 0.27 to 1.71 ± 0.31 mm month-1. Growth rates were higher on Sonneratia alba (1.65 ± 0.69 mm month-1), low on Rhizophora stylosa, Xylocarpus moluccensis, Avicennia marina, Ceriops tagal (0.82 ± 0.16, 0.82 ± 0.18, 0.85 ± 0.18, 0.88 ± 0.28 mm month-1, respectively), and medium on Rhizophora apiculata, Bruguiera parviflora, Bruguiera gymnorrhiza, Rhizophora mucronata (1.19 ± 0.16, 1.22 ± 0.69, 1.25 ± 0.49, 1.31 ± 0.22 mm month-1, respectively). Statistically, growth rates were higher in trees with initial girths more than 50 cm compared to trees with initial girth less than 50 cm on B. gymnorrhiza, C. tagal, and R. mucronata, but these were slower for R. apiculata and S. alba. Between individual trees in six species tested, the differences in diameter growth rate were statistically significant. Growth rates varied among different site conditions, and the effect of soil water salinity on these was significant at higher intertidal sites. Growth rates exhibited seasonal patterns, and these were correlated positively with rainfall and negatively with temperature. The effect of the 2015-2016 El Nino was significant on reduced growth rates.

The purpose of this study was (1) to describe macrozoobenthos and calculate and analyze bio-indexes including density, diversity, domination, and proprietary macrozoobenthos genus found on the beach of Malalayang. (2) inform the condition of habitat sediment granulometry and related to various macrozoobenthos bio-indexes found on the Malalayang Beach. The results of the identification of macrozoobenthos types obtained from the entire research station have obtained macrozoobenthos taxa covering 3 classes, namely: Gastropoda classes include 5 genera, namely Melanella, Margarites, Frigidoalvania, Oenopot, and Cylichna, Crustacean class (2 genera: Pagurus and Hemigrapsus) and Polychaeta classes ( 1 genus: nais). Macrozoobenthos density at Station 1 and Station 3. Overall, station 1 has the highest average density of 29.33 ind./m2; Furthermore, Station 3 has an average density of 23 indv. /m2; And finally Station 2 with a density of 17.67 Ind. /m2. Based on the results of the test, it was concluded that none of the values of the macrozoobenthos diversity index at the research site showed that the H1 acceptance or can be said that the results of the t-test stated that all the recatient research tests were not significantly different meaning the diversity of the entire station tested had the same diversity. The dominance index also obtains values that indicate the condition of the lack of dominance from certain macrozoobenthos genera at the research location.The volume index is obtained that the community is in a stable condition only found at Station 3, namely the rear graduation area in the Malalayang River estuary. Communities that are in depressed conditions are found in the graduation land of station 1 and station 3, as well as the rearstal land of station 2. Other areas obtained by the community are in unstable conditionsThe sediment composition that looks for files to stations at the research site displays diverse conditions. In general, through the graph of the sediment composition produced, at station 1 can be said to have decreased grain size towards land. Physical at Station 2, on the contrary, experienced an increase in a more rough (gravel) sediment on the middle and rear land, and at station 3, the center of the center looks composed of sediments that have a rough size.Keywords: intertidal; macrobenthos; sediment AbstrakTujuan penelitian ini adalah (1) Mendeskripsikan makrozoobenthos serta menghitung dan menganalisis bioindeks meliputi kepadatan, keanekaragaman, dominasi, dan kemerataan genus makrozoobenthos yang terdapat di Pantai Malalayang. (2) Menginformasikan kondisi granulometri sedimen habitat dan kaitannya dengan berbagai bioindeks makrozoobenthos yang terdapat di pantai Malalayang. Hasil identifikasi jenis-jenis makrozoobenthos yang diperoleh dari keseluruhan stasiun penelitian telah diperoleh taksa makrozoobenthos meliputi 3 kelas yaitu: Kelas Gastropoda meliputi 5 Genera yakni Melanella, Margarites, Frigidoalvania, Oenopotadan Cylichna, Kelas Crustacea (2 Genus: Pagurus dan Hemigrapsus) dan Kelas Polychaeta (1 Genus: Nais).Kepadatan makrozoobenthos pada Stasiun 1 dan Stasiun 3,  Secara keseluruhan, Stasiun 1 memiliki rata-rata kepadatan tertinggi yaitu sebesar 29,33 ind./m2; selanjutnya Stasiun 3 memiliki kepadatan rata-rata 23 ind./m2; dan terakhir Stasiun 2 dengan kepadatan 17,67 ind./m2.Berdasarkan hasil uji_t diperoleh kesimpulan bahwa tidak ada satupun dari nilai indeks keanekaragaman makrozoobenthos pada lokasi penelitian menunjukkan terima H1 atau dapat dikatakan hasil uji-t menyatakan bawha semua satisun penelitian yang di uji tidak berbeda nyata artinya keanekaragaman seluruh stasiun yang diuji mempunyai keanekaragaman sama. Indeks Dominansi juga memperoleh nilai-nilai yang menunjukkan kondisi tidak adanya dominasi dari genus makrozoobenthos tertentu pada lokasi penelitian.Indeks kemerataan diperoleh bahwa komunitas berada dalam kondisi stabil hanya terdapat pada Stasiun 3, yaitu area lahan gisik bagian belakang di muara Sungai Malalayang.  Komunitas yang berada dalam kondisi tertekan, terdapat pada lahan gisik bagian depan Stasiun 1 dan Stasiun 3, serta lahan gisik bagian belakang Stasiun 2.  Area lainnya diperoleh komunitas berada dalam kondisi yang labilKomposisi sedimen yang menghampari gisik pada stasiun-stasiun di lokasi penelitian menampilkan kondisi yang beragam.  Secara umum, melalui grafik komposisi sedimen yang dihasilkan, pada Stasiun 1 dapat dikatakan terjadi penurunan ukuran butir ke arah darat. Gisik pada Stasiun 2, sebaliknya mengalami peningkatan sedimen berukuran lebih kasar (kerikil) pada lahan bagian tengah dan belakang, dan pada Stasiun 3, gisik bagian tengah tampak tersusun oleh sedimen yang memiliki ukuran kasar. Kata Kunci: intertidal; makrobenthos; sedimen

Arus merupakan proses pergerakan massa air menuju kesetimbangan yang menyebabkan perpindahan massa air secara horizontal dan vertikal. Penelitian ini diarahkan untuk mendeskripsikan arah dan kecepatan arus permukaan di perairan sekitar Pulau Bunaken serta menganalisis data kecepatan dan arah arus permukaan secara spasial dan temporal (saat pasang dan saat surut) di perairan sekitar Pulau Bunaken. Resultan kecepatan arus saat air bergerak pasang terukur berada pada kisaran 0,05 sampai 2,50 knot, sedangkan saat air bergerak surut berada pada kisaran 0,02 sampai 1,53 knot. Saat air bergerak pasang hampir 50% frekuensi kejadian resultan arusnya berkecepatan < 0,50 knot, saat air bergerak surut sekitar 50% frekuensi kejadiannya berada pada resultan kecepatan antara 0,50 sampai 1,00 knot.  Frekuensi kejadian resultan arah arus saat air bergerak pasang terbanyak mengarah ke Timur, yaitu sebesar 27,27%. Saat air bergerak surut, resultan arah pergerakan arus terbanyak mengarah ke Tenggara, yaitu sebanyak 22,73%. Secara spasial, fluktuasi kecepatan dan arah arus perairan sekitar Pulau Bunaken yang terukur pada skala temporal yang singkat (30 detik) memperlihatkan kondisi relatif konstan. Hanya pada beberapa tempat tertentu memperlihatkan kejadian perubahan baik kecepatan dan arah arusnya.